Treatment of primary rectal adenocarcinoma after prior pelvic radiation: The role of hyperfractionated accelerated reirradiation

Purpose: Previous studies have reported that hyperfractionated accelerated reirradiation can be used as part of multimodality treatment of locally recurrent rectal cancer with acceptable toxicity and promising outcomes. The purpose of this study was to evaluate the outcomes and toxicity of hyperfractionated accelerated reirradiation for patients with primary rectal adenocarcinoma and a history of prior pelvic radiation for other primary malignancies. Methods and materials: We identified 10 patients with a prior history of pelvic radiation for other primary malignancies who were treated with hyperfractionated accelerated reirradiation for primary rectal adenocarcinoma. Radiation therapy was administered with 1.5 Gy twice daily fractions to a total dose of 39 Gy to 45Gy. Results: The median follow-up time was 3.2 years (range, 0.6-9.0 years). Seven of 10 patients received surgery after reirradiation. The 3-year freedom-from-local-progression rate was 62% for all patients and 80% for patients who underwent surgery. The 3-year overall survival rate was 100%, with 3 deaths occurring at 4.7, 6.5, and 9.0 years after reirradiation. One patient had an acute Grade 3 toxicity of diarrhea, and 1 patient experienced a late Grade 3 toxicity of sacral insufficiency fracture. Conclusions: Hyperfractionated accelerated reirradiation was well tolerated with promising rates of freedom from local progression and overall survival in patients with primary rectal cancer with a history of prior pelvic radiation therapy. This approach, along with concurrent chemotherapy and surgery, appears to be a viable treatment strategy for this patient population.